1. Field of the Invention
The present invention relates to a golf club head having a portion with different thickness in a face portion.
2. Description of the Related Art
A conventional metallic golf club head having a portion with different thickness in a face portion was disclosed in JP-A-9-192273. The golf club head of JP-A-9-192273 has a thickness T1 of a central part 3 including a sweet spot of a face forming portion 2 to be formed strong enough to withstand an impact with the ball, and the thickness T2, T3 of the peripheral parts 4, 5 of the central part 3 smaller than that of the central part 3 to have a spring property over the entire face, as shown in FIG. 5.
The golf club head of JP-A-9-192273 has a reduced weight while keeping the strength of the face portion, whereby the size of the head is increased by allocating the reduced weight, or the size of the head is increased without changing the weight of the head. Also, the entire face portion is given a spring property by reducing the thickness of the peripheral part of the face portion, so that the repulsion of the ball is more excellent.
However, the golf club head as described in JP-A-9-192273 was not fully satisfied in the respects of the weight reduction effect, repellency and strength of the face portion, because there was a step difference between the thicker portion and the thinner portion, the thickness of the central part was quite large, and the relationship between the area of the thicker portion and the area of the thinner portion was not minutely examined.
This invention has been achieved in the light of the above-mentioned problems, and it is an object of the invention to provide a golf club head having a portion with different thickness in a face portion, in which the golf club head is fully satisfied in the respects of the weight reduction effect, repellency and strength of the face portion.